196 research outputs found
A virtual environment for the design and simulated construction of prefabricated buildings
The construction industry has acknowledged that its current working practices are in need of substantial improvements in quality and efficiency and has identified that computer modelling techniques and the use of prefabricated components can help reduce times, costs, and minimise defects and problems of on-site construction. This paper describes a virtual environment to support the design and construction processes of buildings from prefabricated components and the simulation of their construction sequence according to a project schedule. The design environment can import a library of 3-D models of prefabricated modules that can be used to interactively design a building. Using Microsoft Project, the construction schedule of the designed building can be altered, with this information feeding back to the construction simulation environment. Within this environment the order of construction can be visualised using virtual machines. Novel aspects of the system are that it provides a single 3-D environment where the user can construct their design with minimal user interaction through automatic constraint recognition and view the real-time simulation of the construction process within the environment. This takes this area of research a step forward from other systems that only allow the planner to view the construction at certain stages, and do not provide an animated view of the construction process
Forensics in Industrial Control System: A Case Study
Industrial Control Systems (ICS) are used worldwide in critical
infrastructures. An ICS system can be a single embedded system working
stand-alone for controlling a simple process or ICS can also be a very complex
Distributed Control System (DCS) connected to Supervisory Control And Data
Acquisition (SCADA) system(s) in a nuclear power plant. Although ICS are widely
used to-day, there are very little research on the forensic acquisition and
analyze ICS artefacts. In this paper we present a case study of forensics in
ICS where we de-scribe a method of safeguarding important volatile artefacts
from an embedded industrial control system and several other source
Market Segmentation Trees
We seek to provide an interpretable framework for segmenting users in a
population for personalized decision-making. The standard approach is to
perform market segmentation by clustering users according to similarities in
their contextual features, after which a "response model" is fit to each
segment to model how users respond to personalized decisions. However, this
methodology is not ideal for personalization, since two users could in theory
have similar features but different response behaviors. We propose a general
methodology, Market Segmentation Trees (MSTs), for learning interpretable
market segmentations explicitly driven by identifying differences in user
response patterns. To demonstrate the versatility of our methodology, we design
two new, specialized MST algorithms: (i) Choice Model Trees (CMTs) which can be
used to predict a user's choice amongst multiple options, and (ii) Isotonic
Regression Trees (IRTs) which can be used to solve the bid landscape
forecasting problem. We provide a customizable, open-source code base for
training MSTs in Python which employs several strategies for scalability,
including parallel processing and warm starts. We provide a theoretical
analysis of the asymptotic running time of our training method validating its
computational tractability on large datasets. We assess the practical
performance of MSTs on several synthetic and real world datasets, showing our
method reliably finds market segmentations which accurately model response
behavior. Further, when applying MSTs to historical bidding data from a leading
demand-side platform (DSP), we show that MSTs consistently achieve a 5-29%
improvement in bid landscape forecasting accuracy over the DSP's current model.
Our findings indicate that integrating market segmentation with response
modeling consistently leads to improvements in response prediction accuracy,
thereby aiding personalization
Market Segmentation Trees
Problem Definition: We seek to provide an interpretable framework for segmenting users in a population for personalized decision-making.
Methodology / Results: We propose a general methodology, Market Segmentation Trees (MSTs), for learning market segmentations explicitly driven by identifying differences in user response patterns. To demonstrate the versatility of our methodology, we design two new, specialized MST algorithms: (i) Choice Model Trees (CMTs), which can be used to predict a user’s choice amongst multiple options and (ii) Isotonic Regression Trees (IRTs), which can be used to solve the bid landscape forecasting problem. We provide a theoretical analysis of the asymptotic running times of our algorithmic methods, which validates their computational tractability on large datasets. We also provide a customizable, open-source code base for training MSTs in Python which employs several strategies for scalability, including parallel processing and warm starts. Finally, we assess the practical performance of MSTs on several synthetic and real world datasets, showing that our method reliably finds market segmentations which accurately model response behavior.
Managerial Implications: The standard approach to conduct market segmentation for personalized decision-making is to first perform market segmentation by clustering users according to similarities in their contextual features, and then fit a “response model” to each segment in order to model how users respond to decisions. However, this approach may not be ideal if the contextual features prominent in distinguishing clusters are not key drivers of response behavior. Our approach addresses this issue by integrating market segmentation and response modeling, which consistently leads to improvements in response prediction accuracy, thereby aiding personalization. We find that such an integrated approach can be computationally tractable and effective even on large-scale datasets. Moreover, MSTs are interpretable since the market segments can easily be described by a decision tree and often require only a fraction of the number of market segments generated by traditional approaches
Superfluid to normal phase transition and extreme regularity of superdeformed bands
We derive the exact semiclassical expression for the second inertial
parameter for the superfluid and normal phases. Interpolation between
these limiting values shows that the function changes sign at the
spin , which is critical for a rotational spectrum. The quantity
turns out to be a sensitive measure of the change in static pairing
correlations. The superfluid-to-normal transition reveals itself in the
specific variation of the ratio versus spin with the
plateau characteristic of the normal phase. We find this dependence to be
universal for normal deformed and superdeformed bands. The long plateau with a
small value explains the extreme regularity of
superdeformed bands.Comment: 30 pages in LaTeX, 6 figures (PostScript). To be published in
Yadernaya Fizika (Physics of Atomic Nuclei), special edition dedecated to the
90th birthday of Prof. I. I. Gurevit
Microscopic Study of Superdeformed Rotational Bands in 151Tb
Structure of eight superdeformed bands in the nucleus 151Tb is analyzed using
the results of the Hartree-Fock and Woods-Saxon cranking approaches. It is
demonstrated that far going similarities between the two approaches exist and
predictions related to the structure of rotational bands calculated within the
two models are nearly parallel. An interpretation scenario for the structure of
the superdeformed bands is presented and predictions related to the exit spins
are made. Small but systematic discrepancies between experiment and theory,
analyzed in terms of the dynamical moments, J(2), are shown to exist. The
pairing correlations taken into account by using the particle-number-projection
technique are shown to increase the disagreement. Sources of these systematic
discrepancies are discussed -- they are most likely related to the yet not
optimal parametrization of the nuclear interactions used.Comment: 32 RevTeX pages, 15 figures included, submitted to Physical Review
Long-range Effects on the Pyroelectric Coefficient and Dielectric Susceptibility of a Ferroelectric Bilayer
Long-range effects on the pyroelectric coefficient and susceptibility of a
ferroelectric bilayer with a ferroelectric interfacial coupling are
investigated by use of the transverse Ising model within the framework of
mean-field theory. The effects of the interfacial coupling and the transverse
field on the pyroelectric coefficient and susceptibility of the bilayer are
investigated by taking into account the long-range interaction. It is found
that the pyroelectric coefficient and susceptibility increase with the decrease
of the magnitude of the long-range interaction and the interfacial coupling
when the temperature is lower than the phase transition temperature. We also
find that the strong long-range interaction, the large transverse field and
weak interfacial coupling can lead to the disappearance of some of the peaks of
the pyroelectric coefficient and susceptibility of the ferroelectric bilayer.
The phase transition temperature increases with the increase of the strength of
the long-range interaction, which is similar to the results obtained in
ferroelectric multi-layers or superlattice.Comment: 23 pages, 11 figure
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